Long-acting reversible contraception like intrauterine devices and progestin implants can prevent unwanted pregnancy up to 20 times better than birth control pills, patches and vaginal rings, according to a study. An intrauterine device, or IUD, is a small copper or hormonal implant that can be inserted in a woman\'s uterus by a doctor, and it works for 10 years to prevent pregnancy. A progestin implant, meanwhile, is inserted in the upper arm and can prevent pregnancy for up to three years. Once in place, these devices prevent unwanted pregnancy as effectively as sterilization, but unlike permanent sterilization, when a woman wants to become pregnant she simply has the device removed. But few women use long-acting reversible contraception, and researchers from the Washington University School of Medicine say cost could be one reason. Since it is not covered by many insurance plans, women might find themselves forking out 700 dollars to buy an IUD and have it inserted. Compare this to 10 dollars to 20 dollars per month for birth control pills, which are generally covered by insurance. Over the long term, however, IUDs are cost-effective; when you break the cost down over a five-year period, IUDs cost about 11 dollars a month, the same as birth control pills. Dr. Jeff Peipert, one of the study authors and vice chair for clinical research at Washington University, said this big initial cost discourages women, since insurance usually does not cover this type of birth control. In the study he conducted, women were allowed to choose which birth control they wanted, free of charge. \"A major surprise was that many people chose long-acting reversible contraceptive (IUD) when barriers were lifted. Around 75 percent of women chose a long-acting reversible contraceptive; the hormonal IUD was the most popular,\" ABC News quoted Peipert as saying. Women\'s health experts also said myths surrounding IUDs, such as they cause infertility or infections, may keep many women from using this option. But careful medical research over the past decade have shown these fears are not true, said Dr. Kevin Ault, associate professor of gynecology and obstetrics at Emory University School of Medicine in Atlanta. Dr. Lauren F. Streicher, assistant professor of obstetrics and gynecology at Northwestern Memorial Hospital in Chicago, said some women might have also heard that if they have not yet had children they should not opt for an IUD. While this is untrue, she does recommend having a doctor who is experienced place IUDs in these women, as placement can be technically difficult. And then there is the fact that many women may not know what an IUD is, or that such an option exists. IUDs are not nearly as highly advertised as birth control pills, doctors said -- at least not yet. \"The reason most women choose pills is a combination of marketing, patient familiarity and comfort level, physician comfort with counseling and insertion, and misconceptions about IUD safety,\" Streicher said. But as more studies like this most recent one emerge, Streicher said, more women may shift to IUDs in the years to come.